Thermic lance

ABSTRACT

A thermic lance which is operated by gaseous combustion and serves for forming openings in concrete, building walls and the like. The lance is equipped with a steel tube packed with a plurality of rods. Oxygen is passed through the tube and the lance ignited to produce an intense heat source that is applied to the material to be cut. The enclosing tube has with the exception of is ends a cross-sectional shape which is other than circular.

United States Patent Inventor Ernst Brandenberger Rapperswilerstrasse 15, Wetzikon, Switzerland App]. No. 787,854 Filed Dec. 30, 1968 Patented Mar. 16, 1971 Priority Jan. 3, 1968 Switzerland 23/68 THERMIC LANCE 6 Claims, 2 Drawing Figs.

U.S. Cl 110/1, 431/99 Int. Cl F23b 7/00, F23d 21/00 Field of Search 431/99; 1 10/22, 1

[56] References Cited UNITED STATES PATENTS 3,260,076 7/1966 l-lumberg 431/99 Primary ExaminerEdward G. Favors Attorney- Flynn and Frishauf the tube and the lance ignited to produce an intense heat source that is applied to the material to be cut. The enclosing tube has with the exception of is ends a cross-sectional shape which is other than circular.

Patented March 16, 1971 Fig. 1

The present invention relates to an improved thermic lance which is operated by gaseous combustion and serves for forming bores or openings in concrete, stone, building walls, severing reinforced concrete and hard to clear material, having an enclosing tube and a plurality of rods located in this enclosing tube.

For ensuring that a combustion process of this kind will be economic, it has been found that it is a matter of considerable importance that the free longitudinal ducts which are defined between the steel rods and the interior of the enclosing tube and serve for the passage of the oxygen should not be too large. Attempts have therefore been made to fill the whole available internal cross-sectional area of the enclosing tube with steel rods. This has, however, entailed difficulties in the insertion of the steel rods, because both the enclosing tube and the steel rods are subject to manufacturing tolerances which, it has been found in practice, prevent the enclosing tube from being filled to an extent corresponding to its geometrical dimensions.

it is an object of the present invention to facilitate filling the whole available internal cross-sectional area of the enclosing tube with steel rods.

It is further object of the invention to reduce the free longitudinal spaces which are defined between the steel rods themselves and the interior of the enclosing tube and which serve for the passage of the oxygen and therefore to reduce the oxygen consumption.

Another object of the invention is to provide commercially available steel tubes so that no expensive profiled tubes must be used.

' The invention also relates to a method comprising the steps of introducing into a circular enclosing tube a plurality of steel rods, the enclosing tube being subsequently deformed, with the exception of at least one of its ends, so that the cross-sectional shape is thereafter other than circular, the deformation is executed in such way that the ducts which extend in the longitudinal direction of the combustion lance and which serve for the passage of the oxygen for combustion being preserved.

The invention will be better understood and objects other than those set forth above, will become apparent, when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings in which FIG. 1 is a view of the thermic lance, partially in section: and

HG. 2 is a cross-sectional view of the thermic lance of FIG. 1 taken along the line lI-II.

The cutting by combustion of bores or openings in building walls by means of consumable oxygen lances takes place in such a way that oxygen of high purity is blown under pressure through a tube 1 filled with steel rods 5 or core rods. To start the iron/oxygen reaction the tip of the lance is preheated to ignition temperature. Oxygen is then fed through the lance, promoting fusion at the lance point and the reaction becomes self-supporting. The heat generated fuses the lance and the flow of slag from the reaction zone is assisted by the velocity of the expelled gases and vapors. By such thermic boring it is possible to bore concrete, rock, stone and hard to clear material and also to severing reinforced concrete. In this way both the tube l and steel rods 5 become consumed and have to be replaced from time to time.

In the production of a thermic lance of this kind a plurality of core rods 5 made of iron and having preferably a circular cross section are packed or introduced into an enclosing tube 11 which is preferably made of unalloyed iron and is circular in its cross-sectional shape. The number of the core rods 5 is so selected that these rods fill out the available space in the enclosing tube in the best possible manner and are maintained in position by a mutual wedging action, although the ease with which the rods are introduced into the enclosing tube is not adversely affected thereby. The enclosing tube is provided at both its ends with a short exterior screw thread 4 so that two of these enclosing tubes can be attached together by means of a connecting sleeve, or one end of the enclosing tube can be connected to a hose pipe or other tube which is connected to a source of the oxygen required for combustion.

As shown more clearly in FIG. 2, when the core rods have been introduced into the enclosing tube, the latter is deformed over its length with the exception of the two end portions thereof, each of which are approximately 2 inches to 4 inches long; this deformation is brought about by pressing the enclosing tube between two parallel cylindrical rollers, which are 'shiftable relative to each other, until the enclosing tube assumes along the deformation zone 2 a substantially oval crosssectional shape with two flat, parallel sides. In this way the internal cross-sectional area of the tube is reduced, and the spaces extending in the longitudinal direction of the enclosing tube, and constituted by the spaces 6 or longitudinal ducts between the individual core rods and by the spaces between the core rods themselves and the enclosing tube, are so reduced that these combined spaces amount to about oneninth to one-eighteenth, and preferably approximately oneeleventh .to one-sixteenth, of the total cross-sectional area of the metal. It is desirable that the ducts for the flow of oxygen should be distributed as uniformly as possible over the whole of the available cross-sectional surface, so as to ensure a uniform combustion at the tip of the lance. It has been found that particularly economical working is possible if the ratio of the cross sections of the surface of the enclosing tube and of the total surface of the core rods lies between 1.4:1 and 1:1, it being assumedthat the values given above for the ratio of the cross-sectional area of the oxygen ducts to the cross-sectional area of the steel is observed.

Tests have shown that with lances of the kind described combustion values can be obtained which, according to the dimension of the enclosing tubes used, are 30-50 percent better than the same lances which have been filled in the best possible manner but which have not undergone deformation of the enclosing tube.

Instead of an oval cross-sectional shape, the enclosing tube may be caused to assume cross-sectional shapes other than circular, for example they may be given triangular, polygonal, semicircular or other shapes.

As material for the enclosing tube commercially available steel gas pipes are used and as material for the steel core rods commercially available rod which are used to reinforce concrete.

Thermic boring and severing equipment is simple, easy to operate and highly mobile and this method is preferred if quietness, simplicity, speed and economy is important.

It will be understood that the present invention is not limited to the specific materials, steps and other specific details described above and may be carried out with various modifications without departing from the scope of the invention as defined in the appended claims.

I claim:

ll. Therrnic lance for gaseous combustion for forming cavities or openings in concrete, stone, building walls, comprising a steel tube, and a plurality of steel core rods enclosed by said tube, said tube having gas connecting means at one end, intermediate spaces being formed between said core rods and said tube extending in the longitudinal direction of said tube serving for the conveyance of gas for combustion, and said tube having a cross-sectional shape other than circular except at least one of its end parts.

2. Thermic lance as defined in claim I, wherein the ratio of the total cross-sectional area of the gas conveyance spaces to the total cross-sectional area of the constituent material of the enclosing tube and of the core rods amounts to 1:9 to 1:18 in the deformed condition of the enclosing tube.

3. Thermic lance as defined in claim ll, wherein the ratio of the combined cross-sectional extent of the gas conveyance spaces to the total cross-sectional area of the constituent material of the enclosing tube and of the core rods amounts to 1:1 1 to 1:16 in the deformed condition of the tube.

thread.

6. Thermic lance as defined in claim 1, wherein the deformed part of said enclosing tube is of substantially oval cross-sectional shape. 

1. Thermic lance for gaseous combustion for forming caVities or openings in concrete, stone, building walls, comprising a steel tube, and a plurality of steel core rods enclosed by said tube, said tube having gas connecting means at one end, intermediate spaces being formed between said core rods and said tube extending in the longitudinal direction of said tube serving for the conveyance of gas for combustion, and said tube having a cross-sectional shape other than circular except at least one of its end parts.
 2. Thermic lance as defined in claim 1, wherein the ratio of the total cross-sectional area of the gas conveyance spaces to the total cross-sectional area of the constituent material of the enclosing tube and of the core rods amounts to 1:9 to 1:18 in the deformed condition of the enclosing tube.
 3. Thermic lance as defined in claim 1, wherein the ratio of the combined cross-sectional extent of the gas conveyance spaces to the total cross-sectional area of the constituent material of the enclosing tube and of the core rods amounts to 1:11 to 1:16 in the deformed condition of the tube.
 4. Thermic lance as defined in claim 1, wherein the ratio of the cross-sectional area of the surface of the enclosing tube to that of the total cross-sectional area of the core rods lies between 1.4:1 and 1:1.
 5. Thermic lance as defined in claim 1, wherein both ends of said enclosing tube are provided with an external screw thread.
 6. Thermic lance as defined in claim 1, wherein the deformed part of said enclosing tube is of substantially oval cross-sectional shape. 